One challenge facing operators today is insufficient upstream bandwidth due to current sub-split frequency plans. A diplexer consists of a common port connected to a cable transporting two way signals, a high pass port connected to a receiver, and a low pass port connected to a transmitter. For example, some cable architectures utilize a fixed diplex filter for sub-split frequencies. One such sub-split frequency plan is 5-42 MHz upstream and 50-1000 MHz downstream. This severely limits upstream bandwidth for the benefit of downstream transmissions. Operators are looking at mid, or even higher, split frequency plans to increase the upstream bandwidth, but this obviously reduces the downstream bandwidth their customers have become accustomed to. Utilizing multiple fixed diplexers or switched diplexers within modems is possible but presents operational problems for modems and increases the expense and complexity of modems employing switched diplexers.